• Journal of the Korean Data and Information Science Society
• /
• v.24 no.1
• /
• pp.105-115
• /
• 2013

As far as the universities in south Korea are concerned, they have to meet the need of the situation as the number of the incoming students are decreasing because of the population-reducing in south Korea. The Ministry of Education Science and Technology is enforcing the restructuring of an universities by evaluating all the universities in Korea by using some indices (employment rate, supplement rate of students etc.). Most of the universities in Korea are widely permitting the changes of the major study as a method to improve the 'supplement rate of students' among some measures. These changes of major study (moving in and moving out) can give rise to difficulties in managing an university because there might be the departments with a small number of students as they moving out from low level departments to high level ones. Moreover, as raising the change rate of the major study, there is no loss from the university's point of view but a department could be in a difficult situation. The purpose of this study is to grasp the characteristics for changing major study by a general statistical analysis and graphs produced by a social network analysis with the D university's case. The results of this study are as follows; (a) category is from the engineering to humanity-society, (b) entrance level is from low to high, and (c) employment rate is from low to high as well.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.4
• /
• pp.295-300
• /
• 2007

A new characterization method using a porous plug model was proposed to determine the degree of sulfonation (DS) of ionomer binder with respect to the membrane used in membrane-electrode assemblies (MEAs) and to analyze the fraction of proton pathways through ionomer-catalyst combined electrodes in MEAs for polymer electrolyte fuel cells (PEFCs). Sulfonated poly(ether ether ketone) was prepared to use a polymeric electrolyte and laboratory-made SPEEK solution (5wt.%, DMAc based) was added to catalyst slurry to form catalyst layers. In case of the SPEEK-based MEAs in this study, DS of ionomer binder for catalyst layers should be the same or higher than that of the SPEEK membrane used in the MEAs. The porous plug model suggested that most of protons were via the ionomer binder (${\sim}92.5%$) bridging the catalyst surface to the polymeric electrolyte, compared with the pathways through the alternative between the interstitial water on the surface of ionomer binder or catalyst and the ionomer binder (${\sim}7.3%$) and through only the interstitial water on the surface of ionomer or catalyst (${\sim}0.2%$) in the electrode of the MEA comprising of the sulfonated poly(ether ether ketone) membrane and the 5wt.% SPEEK ionomer binder. As a result, it was believed that the majority of proton at both electrodeds moves through ionomer binder until reaching to electrolyte membrane. The porous plug model of the electrodes of MEAs reemphasized the importance of well-optimized structure of ionomer binder and catalyst for fuel cells.

• Journal of Periodontal and Implant Science
• /
• v.31 no.3
• /
• pp.555-564
• /
• 2001

The purpose of this study is to evaluate the bioresorbability of Calcium Polyphosphate added with $Na_2O$ and chitosan. Though calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To solve these problem, we developed a new ceramic, calcium polyphosphate(CPP), and report the biologic response to CPP in extraction sites of beagle dog. Porous CPP granules were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. CPP granules added with $Na_2O$ and chitosan were implanted in extraction sockets and histologic observation were performed at 12 weeks later. Histologic observation at 12 weeks revealed that CPP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CPP granules added with chitosan were well adatped without any adverse tissue reaction and resorbed slowly and spontaneously. CPP granules added with $Na_2O$ and chitosan show multinucleated giant cells and osteoblast-like cells around grafted material and newly formed bone. This result revealed that CPP, regardless of its additive component, had a high affinity for bone and had been resorbed slowly. From this results, it was suggested that CPP is promising ceramic as a bone substitute and addition of $Na_2O$ and chitosan help biodegradation. In further study , it will be determined which concentration of $Na_2O$ help biodegradation and the other additive components increase the degradation rate.

• Journal of Korea Game Society
• /
• v.9 no.3
• /
• pp.15-22
• /
• 2009

Our society is the information-oriented knowledge society which demands the ability how to use computers to all members of the society and is the aging society which the old people 60 or older exist plentifully. But in our society, there are rarely the computers for the old people which are considered their body limit. In this research, we proposed a grip type Hangul(Korean alphabet)interface which are designed under the consideration for the body limit of the old people. The comparison analysis of the proposed Hangul interface is accomplished with the keyboard(ME TOO SV01) for old persons and the key buttons of the old person cellular phone(LG KV-3900) as existing products. The comparison analysis consists of quantitative evaluation as measurements and qualitative evaluation as a survey of the satisfaction levels of 10 older persons. The results of the quantitative evaluation show that the proposed Hangul interface is the best one in the human-technology-design, the number of input buttons which requires moving of user's fingers, the maximum range of moving of user's fingers, and the number of the fingers to use text inputs. The survey results of the satisfaction levels show that interface shape, and input button's positions have best levels and they show that input button's gaps and ease of use have the second levels but their points are almost same with the best points of the keyboard.

• Journal of Ocean Engineering and Technology
• /
• v.2 no.2
• /
• pp.112-121
• /
• 1988

A study on friction welding of carbon steel bar (SM45C) to chrome molybedenum steel bar(SCM4) is examined experimentally through tensile test, hardness test, microstructure test and fatigue test. so, this paper deals with optimizing the welding concitions and analyzing various mechanical properties about friction welds of SM45C to SCM4 steel bars. The results obtained are summarized as follows; 1) For friction welded joints of SM45C to SCM4 steel bars, the total upset(U)increases linearly with an increase of heating time ($t_{1}$) till 6s. 2) The determined optimum welding conditions are heating time ($t_{1}$)2s, upsetting time($t_{2}$), 3s, heating pressure($p_{1}$), 4kgf/$mm^{2}$(39.2MPa), upsetting pressure($p_{2}$, 8kgf/mm$^{2}$(78.4MPa) and rotating speed(N), 2, 000rpm when the total upset(U) is 3.4mm, resulting in a computed relationship between the joint tensile strength .sigma.$_{t}$ (kgf/mm$^{2}$and the total upset U(mm); .sigma.$_{t}$ =$0.21U^{3}$ - $3.38U^{2}$ +17.03U + 66.00 3) As the elongation is increased more and more, the fracture position becomes away from weld interface and the fractures are similar to those of SM45C. Fracture is taken place on SM45C side. 4) The weld interface of two dissimilar materials is mixed strongly, and the heat affected zone is about 2.0mm at SM45C while about 2.7 mm at SCM4 side. Therefore, the welded zone and heat affected zone are very narrow, comparing with those of the joints welded by the other welding methods. 5) The fatigue strengths at N=10$^{6}$ cycles of SM45C, SCM4 and friction welded joints are 23kgf/$mm^{2}$, 33kgf/$mm^{2}$(220.5 MPa), and 22.5kgf/$mm^{2}$(220.5MPa) respectively, and fracture at friction welded joint takes place at the side of SM45C. 6) The hardness of the friction weld interface is 3 times higher than that of base metal. 7) Fatigue strength of friction welded joint is higher than that of base metal. 8) Notch sensitivity factor of friction welded joint is lower than that of base metal.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.4
• /
• pp.570-574
• /
• 2011

This study was conducted to investigate the quality characteristics of dumpling shells with added Pleurotus eryngii powder (PP) (2%, 4%, 6%). The weight after cooking and volume of the dumpling shells increased with the addition of PP. The water absorption of the dumpling shells was not significantly different by the addition of PP. Turbidity after cooking increased and hardness decreased by adding PP. The L value after cooking decreased with the addition of PP, and the b value was highest when the content of PP was 6%. Adhesiveness increased by adding PP and springiness decreased when PP content was above 4%. Chewiness and gumminess decreased by adding the powder. There were no differences among the control, 2%, and 4% samples in cohesiveness values, but cohesiveness significantly decreased with the addition of 6% of powder. Color characteristics showed low values when PP was added at more than 6% according to sensory characteristics tests. No significant differences were found in flavor, taste, smoothness, moisture, or adhesiveness of the dumpling shells after cooking according to additions of PP. Chewiness was higher by adding PP compared to the control, but no significant differences were found by additions of PP.

• Physical Therapy Korea
• /
• v.9 no.2
• /
• pp.61-81
• /
• 2002

The purposes of this research were to investigate home care rehabilitation services in rural areas and to collect basic data about disabled persons necessary when for carrying out rehabilitation services. Respondents were selected from six of a total of eight townships (Myon) and one town (Eup) in the Wonju city area. Wonju is in Kangwon Province (Do). Of a total of 338 names provided by the Myon offices, 298 persons were located and included registered and non-registered persons. Conditions included stroke, spinal cord injury, and cerebral palsy in addition to disabilities classified as first, second or third degree, in the case of registered cases. Respondent demographic characteristics, medical characteristics, rehabilitation service needs, willingness to receive rehabilitation service and individual opinions regarding rehabilitation services were analysed by frequency and percentage. The results were as follows: 1) Rehabilitation services received by disabled persons living at home in the rural areas surrounding Wonju city were medical rehabilitation (41.7%), diagnosis (36.5%), rehabilitation assistive devices (7.6%), social assistance (7.1%), rehabilitation counseling (3.0%), vocational rehabilitation (1.8%), educational rehabilitation (1.6%) and housekeeping services (0.5%). The majority of rehabilitation services were medical rehabilitation provided at hospitals and oriental medicine hospitals. 2) Sixty point eight percent of respondents expressed their willingness to receive home care rehabilitation services. Needs expressed were highest for medical rehabilitation (27.0%), followed by social assistance (19.4%), medical examination (12.4%), physician-generated diagnosis in the home setting (11.6%), sociopsychological rehabilitation (9.3%), vocational rehabilitation (7.6%), rehabilitation engineering (6.0%), educational rehabilitation (3.3%), and housekeeping services (3.3%). 3) Rehabilitation service needs were analyzed by severity classification: 65.8% of first degree, 62.7% of second degree and 55.6% of third degree disability classification, and 62.7% of non-registered disabled individuals responded that rehabilitation service was necessary. 4) Rehabilitation service needs were also analyzed by diagnosis: 62.6% of stroke, 85.5% of amputation, 60.0% of spinal cord injury and 52.4% of traumatic brain injury respondents answered positively that they were willing to receive rehabilitation service if it were to be provided. Rehabilitation service utilization data of disabled individuals living at home in rural areas were investigated and their rehabilitation needs analyzed. This critical information can be used when community-based rehabilitation programs for disabled persons living at home are planned for provision out of a public health center or when community-based rehabilitation welfare policy is formulated.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.3
• /
• pp.93-98
• /
• 2005

The crystal growth of calcite at a low temperature range was carried out by the hydrothermal method using amorphous calcium carbonate which has excellent solubility in water. Amorphous calcium carbonate was prepared by the wet chemical reaction of a stoichiometric mixture of $CaCl_2\;and\;Na_2CO_3$. An important factor was the reaction temperature and time taken in preparation of the amorphous calcium carbonate. From the solubility results calculated by the weight loss method, $NH_4NO_3$ solutions were found to be the most promising solvents to grow calcite single crystals. The hydrothermal conditions for high growth rates of calcite single crystals were as follows: starting material: amorphous calcium carbonate, solvent: 0.01 m $NH_4NO_3$, temperature: $180^{\circ}C$, duration: 30 days. And properties of calcite single crystals were follows: dislocation density: $10^6{\sim}10cm^{-2}$, UV-visible transmittance: about 80% from 190 to 400 nm and birefringence: $0.17{\sim}0.18$. Also, it can be known from the FT-IR results that the absorption peak by injection of $HCO_3^-\;and\;OH^-$ ions was not shown.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.5
• /
• pp.93-101
• /
• 2005

The formation of slopes is unavoidable under the special circumstance of Korea where $7%$ of the whole area are composed of mountains and civil engineering projects such as road and site developments are increasing with industrial development and horizontal expansions of urban area. Stability of slopes is one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall is concentrated in summer season and the localized torrential downpour is getting more frequent recently. As a result of these circumstances, partial slope failures by debris flow of the high water content soils occur frequently in cut soil slopes. In this case of debris flow slope failure, slope declination method is selected fur the stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. For debris flow failure slopes, this study secured the safety of slopes by preventing the inflow of rainwater and scour using geosynthetics-reinforced embankment, and created nature-friendly slopes by planting trees on the slopes.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.35 no.5
• /
• pp.82-91
• /
• 2007

Currently, bridges are regarding as the structure with formative, scenic and environmental values more than their function as simple passageways. Because an attempt to work on the diversity of the bridge types and installation of the large structures on bridge are part of the project of the regional amenity enterprises, a study that harmonizes bridges with landscape is needed at this point in time. This background can influence the direction of bridge landscapes that considers local features by analysis of visual preferences on a bridge simulated scene. The results were as follows: analyzing the change of the simulated landscape image, forest landscape are damaged by the input of a bridge which was natural, harmonic and intimate. On the other hand, when a bridge was inserted into the ocean landscape, it was thought to improve the ocean landscape, especially, upper part form of arch bridge various or suspension bridge were improved in polished and various image. The insertion of a bridge into an urban landscape change from a negative image to a beautiful, harmonic and attractive image. The intimate, harmonic and natural image of a rural landscape was damaged by inserting a bridge. As analysis result about change of landscape preference by input of bridge, there is difference between before and after as input the bridge, and bridge influences as main object in the simulated scene. Visual preference was the highest in the ocean landscape, and the lowest in the suspension bridge in the rural landscape. The complicated shape of bridge follows on the background type difference certainly appear. Thee simulated scene preference except the urban landscape of the simulated scene fell generally Especially, fall of preference of girder bridge in the forest and ocean landscape, suspension bridge in the rural landscape appeared notedly.